The invention relates to triazole compounds and to the use of such compounds. Said compounds have valuable therapeutic properties and can be used to treat disorders which respond to dopamine D3 receptor ligands,
Compounds which are of the type under discussion here and have physiological activity have been disclosed. U.S. Pat. Nos. 4,338,453, 4,408,049 and 4,577,020 describe triazole compounds which have antiallergic activity.
Neurons receive their information inter alia via G protein-coupled receptors. There are numerous substances which exert their effect via these receptors. One of them is dopamine.
Confirmed findings on the presence of dopamine and its physiological function as neurotransmitter have been published. Cells which respond to dopamine are connected with the etiology of schizophrenia and Parkinson""s disease. These and other disorders are treated with drugs which interact with dopamine receptors.
By 1990, two subtypes of dopamine receptors had been clearly defined pharmacologically, namely D1 and D2 receptors.
Sokoloff et al., Nature 1990, 347: 146-151, found a third subtype, namely D3 receptors. They are expressed mainly in the limbic system. The D3 receptors differ structurally from the D1 and D2 receptors in about half the amino-acid residues.
The effect of neuroleptics has generally been ascribed to their affinity for D2 receptors. Recent receptor-binding studies have confirmed this. According to these, most dopamine antagonists, like neuroleptics, have high affinity for D2 receptors but only low affinity for D3 receptors.
We have now found, surprisingly, that the compounds according to the invention have a high affinity for the dopamine D3 receptor and only a low affinity for the D2 receptor. They are thus selective D3 ligands.
The present invention therefore relates to triazole compounds of the formula I: 
where
A is a straight-chain or branched C1-C18-alkylene group which may comprise at least one group selected from O, S, NR3, CONR3, NR3CO, COO, OCO, C3-C6-cycloalkylene or a double or triple bond,
X is a radical of the formula: 
R1 is H, CO2R3, NR3R4, OR4, C3-C6-cycloalkyl or C1-C8-alkyl which is unsubstituted or substituted by OH, OC1-C8-alkyl or halogen;
R2 has the meanings indicated for R1 or is CF3, SR3, halogen or CN;
R3 is H or C1-C8-alkyl which is unsubstituted or substituted by OH, OC1-C8-alkyl, phenyl or halogen;
R4 has the meanings indicated for R3 or is COR3 or CO2R3;
Ar is phenyl, pyridyl, pyrimidyl or triazine, where AR may have from one to four substituents which are selected, independently of one another, from OR4, C1-C8-alkyl, C2-C6-alkenyl, C2-C6-alkynyl, halogen, CN, CO2R3, NO2, SO2R3, SO3R3, NR3R4, SO2NR3R4, SR3, CF3, CHF2, a 5- or 6-membered carbocyclic aromatic or nonaromatic ring and a 5- or 6-membered heterocyclic aromatic or nonaromatic ring having 1 to 4 hetero atoms selected from O, S and N, where the carbocyclic or heterocyclic ring may be unsubstituted or substituted by C1-C8-alkyl, halogen, OC1-C8-alkyl, OH, NO2 or CF3 and where Ar may also be fused to a carbocyclic or heterocyclic ring of the type defined above, and the salts thereof with physiologically tolerated acids.
The compounds according to the invention are selective dopamine D3 receptor ligands which intervene regioselectively in the limbic system and, because of their low affinity for the D2 receptor, have fewer side effects than classical neuroleptics, which are D2 receptor antagonists. The compounds can therefore be used to treat disorders which respond to dopamine D3 receptor antagonists or agonists, eg. for treating disorders of the central nervous system, in particular schizophrenia, depression, neuroses and psychoses. They can additionally be used to treat sleep disorders and nausea and as antihistamines.
Within the scope of the present invention, the following terms have the meanings indicated below:
Alkyl (also in radicals such as alkoxy, alkyl-amino etc.) means a straight-chain or branched alkyl group having 1 to 8 carbon atoms, preferably 1 to 6 carbon atoms and, in particular, 1 to 4 carbon atoms. The alkyl group can have one or more substituents which are selected, independently of one another, from OH and OC1-C8-alkyl.
Examples of an alkyl group are methyl, ethyl, n-propyl, i-propyl, n-butyl, isobutyl, t-butyl etc.
Alkylene stands for straight-chain or branched radicals having, preferably, 2 to 15 carbon atoms, particularly preferably 3 to 10 carbon atoms.
The alkylene groups may comprise at least one of the abovementioned groups. This canxe2x80x94just like the double or triple bond mentionedxe2x80x94be arranged in the alkylene chain at any point or at the end of the chain so that it connects the chain to the triazole residue. The latter is preferred. When the alkylene group comprises a double or triple bond, it has at least three carbon atoms in the chain.
Halogen is F, Cl, Br, I and, in particular, Cl, Br, I.
R1 and R2 are preferably, independently of one another, H, C1-C8-alkyl, NR3R4 or OR4.
Ar can have one, two, three or four substituents. They are preferably selected, independently of one another, from halogen, CF3, CHF2, NR3R4, OR4, NO2, C1-C8-alkyl, OC1-C8-alkyl, SR3 and CN, where R3 and R4 have the abovementioned meanings.
If one of the substituents of Ar is C1-C8-alkyl, a branched radical, in particular the isopropyl or t-butyl group, is preferred.
Ar preferably has at least one substituent and is, in particular, 
where D1, D2 and D3 are, independently of one another, CR or N, and R, X and Y are H or are the substituents of the radical Ar indicated above or below.
Ar is preferably unsubstituted or substituted phenyl, 2-, 3- or 4-pyridinyl or 2-, 4(6)- or 5-pyrimidyl.
When one of the substituents of the radical Ar is a 5- or 6-membered heterocyclic ring, examples thereof are a pyrrolidine, piperidine, morpholine, piperazine, pyridine, pyrimidine, triazine, pyrrole, thiophene, thiazole, imidazole, oxazole, isoxazole, pyrazole or thiadiazole residue.
When one of the substituents of the radical Ar is a carbocyclic radical, it is, in particular, a phenyl, cyclopentyl or cyclohexyl radical.
When Ar is fused to a carbocyclic or heterocyclic radical, Ar is, in particular, a naphthalene, di- or tetrahydronaphthalene, quinoline, di- or tetrahydroquinoline, indole, dihydroindole, benzimidazole, benzothiazole, benzothiadiazole, benzopyrrole or benzotriazole residue.
X is preferably 
A preferred embodiment comprises compounds of the formula I where A is C3-C10-alkylene which comprises at least one group which is selected from O, S, NR3, cyclohexylene, in particular 1,4-cyxclohexylene, and a double or triple bond, where R3 is as defined above.
Another preferred embodiment comprises compounds of the formula I where
R1 is H, OR4 where R4 is H or C1-C8-alkyl, or C3-C6-cycloalkyl or C1-C8-alkyl which is unsubstituted or substituted by OH, OC1-C8-alkyl or halogen;
R2 is H, C1-C8-alkyl which is unsubstituted or substituted by OH, OC1-C8-alkyl or halogen, or NR3R4 where R3 and R4 are, independently of one another, H, phenyl-C1-C8-alkyl or C1-C8-alkyl, or OR4 where R4 is H or C1-C8-alkyl, or CF3;
A is as defined in claim 3, and
Ar is phenyl, pyridyl or pyrimidyl which may have one, two, three or four substituents which are selected from H, C1-C8-alkyl which is unsubstituted or substituted by OH, OC1-C8-alkyl or halogen, or OR4 where R4 is H, C1-C6-alykl [sic] which is unsubstituted or substituted by OH, OC1-C8-alkyl or halogen, or CHF2, CF3, CN, Halogen, C2-C6-alkenyl, C2-C6-alkynyl, phenyl, naphthyl and a 5- or 6-membered heterocyclic aromatic radical with 1 to 3 hetero atoms selected from O, N and S.
Another preferred embodiment comprises compounds of the formula I where
R1 is H or C1-C8-alkyl which is unsubstituted or substituted by OH, OC1-C8-alkyl or halogen;
R2 is H, C1-C8-alkyl which is unsubstituted or substituted by OH, OC1-C8-alkyl or halogen, or NR3R4 where R3 and R4 are, independently of one another, H or C1-C8-alkyl, or OR4 where R4 is H or C1-C8-alkyl, or CF3;
A is C1-C10-alkylene which may comprise and oxygen or sulfur atom or the group NR3 where R3 is as defined above;
Ar is phenyl which may have one to four substituents which are selected, independently of one another, from H, CN, SR3, halogen, C1-C8-alkyl which is unsubstituted or substituted by OH, OC1-C8-alkyl or halogen, or phenyl, naphthyl, OR4, NO2, NR3R4, CHF2 and CF3, where R3 and R4 have the stated meanings.
Particularly preferred in this connection are the compounds of the formula I where
A is SC3-C10-alkylene, OC3-C10-alkylene or NR3xe2x80x94C3-C10-alkylene, where R3 is H or C1-C8-alkyl,
R1 is H or C1-C8-alkyl;
R2 has the abovementioned meanings;
X is 
Ar is phenyl which has one to four substituents which are, independently of one another, H, C1-C8-alkyl, OC1-C8-alkyl, CHF2, CF3 or CN.
Ar has, in particular, two substituents which are located in positions 3 and 5, with one substituents being CF3, CHF2 or C1-C8-alkyl and the other substituent being H or C1-C8-alkyl.
Another preferred embodiment comprises compounds of the formula I where
Ar is pyrimidinyl which has one to three substituents which are selected, independently of one another, from H, C1-C8-alkyl, phenyl, naphthyl, C3-C6-cycloalky, OH, OC1-C8-alkyl, halogen, CN, CF3, CHF2 and a 5- or 6-membered heterocyclic aromatic radical with 1 to 3 hetero atoms selected from O, N and S;
R1 is H or C1-C8-alkyl which is unsubstituted or substituted by OH, OC1-C8-alkyl or halogen,
R2 is H, NR3R4 or OR4 where R3 and R4 are, independently of one another, H, C1-C8-alkyl or phenyl-C1-C8-alkyl;
A is C1-C10-alkylene which may comprise at least one group selected from O, S, NR3 where R3 is H or C1-C8-alkyl, and a double or triple bond; and
X is as defined above.
Another preferred embodiment comprises compounds of the formula I where
Ar is pyridinyl which has one to four substituents which are selected, independently of one another, from H, C1-C8-alkyl, phenyl, naphthyl, OH, OC1-C8-alkyl, halogen, CF3, CN, C2-C6-alkenyl, C2-C6-alkynyl and a 5- or 6-membered heterocyclic aromatic radical with 1 to 3 hetero atoms selected from O, N and S;
R1 is H, C1-C8-alkyl, C3-C6-cycloalkyl or OR4 where R4 is H or C1-C8-alkyl which is unsubstituted or substituted by OH, OC1-C8-alkyl or halogen; and
R2, A and X are as defined above.
The invention also embraces the acid addition salts of the compounds of the formula I with physiologically tolerated acids. Examples of suitable physiologically tolerated organic and inorganic acids are hydrochloric acid, hydrobromic acid, phosphoric acid, sulfuric acid, oxalic acid, maleic acid, fumaric acid, lactic acid, tartaric acid, adipic acid or benzoic acid. Other acids which can be used are described in Fortschritte der Arzneimittelforschung, Volume 10, pages 224 et seq., Birkhxc3xa4user Verlag, Basle and Stuttgart, 1996.
The compounds of the formula [sic] I may have one or more centers or asymmetry. The invention therefore includes not only the racemates but also the relevant enantiomers and diastereomers. The invention also includes the tautomeric forms in each case.
The compounds of the formula [sic] I can be prepared by methods similar to conventional ones as described, for example, in Houben Weyl xe2x80x9cHandbuch der Organischen Chemiexe2x80x9d, 4th Ed., Thieme Verlag, Stuttgart 1994, Volume E8/d, pages 479 et seq.; and A. R. Katritzky, C. W. Rees (ed.) xe2x80x9cComprehensive Heterocyclic Chemistryxe2x80x9d, 1st Ed. Pergamon Press 1984, in particular Vol. 5, part 4a, pages 733 et seq. and literature cited therein. The process for preparing the compounds comprises
i) reacting a compound of the general formula II: 
where Y is a conventional leaving group, with a compound of the general formula III
Hxe2x80x94Xxe2x80x94Ar
ii) to prepare a compound of the formula I where A is an oxygen or sulfur atom or NR3:
a) reacting a compound of the general formula IV: 
where Z1 is O, S or NR3 and A1is C0-C18-alkylene, with a compound of the general formula VI
Y1xe2x80x94A2xe2x80x94Xxe2x80x94Ar
where Y1 has the abovementiones meanings, and A2 is C1-C18-alkylene, where A1 and A2 together have 1 to 18 carbon atoms;
iii) to prepare a compound of the formula I where A comprises the group COO or CONR3:
a) reacting a compound of the general formula VII: 
where Y2 is OH, OC1-C8-alkyl, Cl or, together with CO, is an activated carboxyl group, and A1 has the abovementioned meanings, with a compound of the formula VIII:
Z1xe2x80x94A2xe2x80x94Xxe2x80x94Ar
where A2 has the abovementioned meanings, and Z1 is OH or NHR3,
iv) to prepare a compound of the formula I where A comprises the group OCO or NR3CO:
a) reacting a compound of the formula IV 
where Z1 is O or NR3, with a compound of the formula X:
Y2COxe2x80x94A2xe2x80x94Xxe2x80x94Ar
where X and Y2 have the abovementioned meanings, and where R1, R2, A, X and Ar have the abovementioned meanings.
The reactions described above generally take place in a solvent at from room temperature to the boiling point of the solvent used. Examples of solvents which can be used are ethyl acetate, tetrahydrofuran, dimethylformamide, dimethoxyethane, toluene, xylene or a ketone, such as acetone or methyl ethyl ketone.
An acid acceptor is present if required. Suitable acid acceptors are inorganic bases such as sodium or potassium carbonate, sodium methoxide, sodium ethoxide, sodium hydride or organic bases such as triethylamine or pyridine. The latter may also serve as solvents.
The crude product is isolated in a conventional way, for example by filtration, removal of the solvent by distillation or extraction from the reaction mixture. The resulting compound can be purified in a conventional way, for example by recrystallization from a solvent, chromatography or conversion into an acid addition compound.
The acid addition salts are prepared in a conventional way by mixing the free base with the appropriate acid, possibly in solution in an organic solvent, for example a lower alcohol such as methanol, ethanol or propanol, an ether such as methyl t-butyl ether, a ketone such as acetone or methyl ethyl ketone, or an ester such as ethyl acetate.
The abovementioned starting materials are disclosed in the literature or can be prepared by known processes.
To treat the abovementioned disorders, the compounds according to the invention are administered in a conventional manner orally or parenterally (subcutaneously, intravenously, intramuscularly, intraperitoneally). Administration can also take place with vapors or sprays through the nasopharyngeal space.
The dosage depends on the age, condition and weight of the patient and on the mode of administration. As a rule, the daily dose of active substance is about 10 to 1000 mg per patient and day on oral administration and about 1 to 500 mg per patient and day on parenteral administration.
The invention also relates to pharmaceutical compositions which contain the compounds according to the invention. These compositions are in the usual solid or liquid pharmaceutical administration forms, for example as tablets, film-coated tablets, capsules, powders, granules, sugar-coated tablets, suppositories, solutions or sprays. The active substances can in these cases be processed with conventional pharmaceutical aids such as tablet binders, fillers, preservatives, tablet disintegrants, flow regulators, plasticizers, wetting agents, dispersants, emulsifiers, solvents, release-slowing agents, antioxidants and/or propellant gases (cf. H. Sucker et al., Pharmaceutics Technologie, Thieme-Verlag, Stuttgart, 1978). The administration forms obtained in this way normally contain the active substance in an amount from 1 to 99% by weight.
The following examples serve to explain the invention without limiting it.